[CCoE Notice] MS Thesis Defense Announcement - Vinay Nuka

[ccoecomm at Central.UH.EDU]

[Dissertation Defense Announcement at the Cullen College of Engineering]

Enhancing Ordering of Block Copolymer Thin Films with Ionic Liquid



Vinay Nuka

November 2, 2022;   2:00 PM - 3:00 PM

Zoom: https://urldefense.com/v3/__https://us04web.zoom.us/j/72606300631?pwd=NHW5GWmAaNVzbDhTVJRac34shPK2CC.1__;!!LkSTlj0I!EJ2_fvdA-UAIMC3DOmaq7zfK_fnqNjGlzlmvxWjZkMhfaB3Joz1zTX53NzoBUlGUB8uhteMXt0Dgx6ULjGBmr4J1LAI$  <https://urldefense.com/v3/__https:/www.google.com/url?q=https:**Aus04web.zoom.us*j*72606300631*pwd*3DNHW5GWmAaNVzbDhTVJRac34shPK2CC.1&sa=D&source=calendar&usd=2&usg=AOvVaw2lv4ZDZ7WOhlDMhVv--yG0__;Ly8vLz8l!!LkSTlj0I!B0cwt2HM0EFYYXhLSF_auLBhfO_I4TJlKAFjjAsoTc0FKW8xoDXLyy2h3VPDRQRfV4MnXcNU3jidJwaIypDZU5-R$>

Zoom meeting ID and passcode: 726 0630 0631, thesis



Committee Chair:
Alamgir Karim, Ph.D.

Committee Members:
Jeremy Palmer, Ph.D. | Devin L Shaffer, Ph.D.

Abstract

Block copolymer self-assembly has been studied extensively because of the broad spectrum of applications it serves in technological devices from ion conduction membranes and transistors to nanowire array antennas. Microphase separation is a phenomenon where the molecular chains in the block copolymer blend -A-B- begin to become mobile and interact above the glass transition temperature Tg such that the contact area between the monomers A and B is reduced. Methods such as thermal annealing, solvent vapor annealing, and direct immersion annealing have been utilized to achieve equilibrium morphological structures based on several parameters like polymer density, area fractions of the monomer units, and the desired nanostructure. Recent research has shown that employing ionic liquid in concentrations as low as 2 – 4% into the polymer film considerably reduces the annealing/processing time to achieve phase separation. This work shows that inducing Ionic liquid (IL) in large concentrations, ranging from 0% to 150%, can drive phase separation in as cast state without any annealing procedures. PS-b-PMMA polymers of various molecular weights in the lamellae regime have been considered to study their response to different ionic liquid concentrations. Morphological structures and molecular features have been analyzed with atomic force microscopic (AFM) and grazing incident small angle x-ray scattering (GISAXS) scans. For polymers to phase separate, χN should be greater than 10.5. Since the flory huggins parameter (χ) belongs at equilibrium, all the polymer films have been annealed to reach equilibrium state. χ has been calculated for all the polymer systems to show the trends with the help of domain lengths of polymers in annealed films. This can serve a long way in reduce the processing period of the polymer films and moreover the scientific study opens the key to further research about the polymer domain – IL interactions. Stable morphologies of the phase separated films offer myriad applications varying from nanopatterning, structure imprinting, and nanolithography in core functional materials to enhanced energy storage, functional surface topologies, and sensitive smart screens.

[Engineered For What's Next]


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